1. Field of the Invention
The present invention generally relates to a manufacturing method for lenticular sheet products, and more particularly, the present invention relates to a manufacturing method for producing flexible, optical lenticular sheets having high clarity lens arrays located thereon in pre-selected areas operable for use with consumer products.
2. Description of the Related Art
In the commercial industry, it is often desirable to impart visual effects such as three dimensionality or motion characteristics upon packages or labels of consumable products and the like. Due to expense and ease of design, regular print advertising was the pre-eminent and preferred form used on consumables. Regular print advertising is accomplished by printing, two-dimensional, non-movable information using words and pictures or graphics on packaging, labels, magazines, newspapers, brochures, fliers, posters, billboards, and signs. While some conventional print advertisements and packaging are interesting, most are not. The primary purpose of good advertisement in packaging is to attract the attention of the reader or customer and convey the desired information. Unfortunately, many printed signs, advertisements and packages do not attract the attention of the desired audience or customers. As such, the use of products having lenticular effects has become increasingly popular.
A reverse printed lenticular sheet has the ability to attract ones attention by presenting an image that has depth, morphing characteristics, and/or can appear to have movement or the capability to flip from one image to another. A package or label having a printed lenticular sheet image on a store shelf has the ability to draw ones attention for a longer period of time than comparable non-lenticular packages. A lenticular sheet having a clear surface offers additional protection to the print on the reverse side from environmental hazards.
A disadvantage of and areas of concern for lenticular sheets is the inability to clearly read small type, bar codes and such through a lenticular lens. By way of example, a package or container containing a medication must have clear and easy to read directions, warnings and/or disclaimers. By way of another example, a credit or debit card and identification cards like drivers license have small print which must be clearly visible but which could also benefit from having a portion of the card with a lenticular image.
Known lenticular lenses, or micro lenses, as used in imaging are typically elongated, lineal or dot patterned across an entire transparent sheet or web such that an image may be seen therethrough with the desired visual effect. The lenses can be either convex or concave in configuration. In addition, some lenses can be elliptical in shape. Typically, the lenses have a pre-determined radius of curvature and a pre-determined uniform pitch or repeat pattern. Lenticular lenses are thin, transparent lenses that are flat on one side and include a plurality of parallel, linear, side-by-side lenticules—elongate, convex or concave lenses—on a second side. Typically, an image is printed on the flat side to create a visual effect of zoom-in, zoom-out, steroscoping, three-dimensional sequencing, or movement of the image when viewed through the lenticules on the opposing side. The combination of the lenses and an image is referred to as a “lenticular assembly.”
Prior art lenticular assemblies are manufactured in a continuous web with the lenticules being parallel to the longitudinal or latitudinal axis of the entire web. Manufacture of lenses may be performed in a variety of ways. In one example, lens shapes are engraved on precision engraving and diamond turning machines into special metal cylinders and polished to a high luster. The lenses are then index/step and repeat engraved to extremely high accuracies measured in the millionths of an inch onto a flexible, transparent sheet using an extrusion process or other known conventional means.
The images used for lenticular assemblies are produced, be they for morph, zoom, flip or 3-dimensional effects, by combining or interlacing a selected image on a computer such that the image is produced in a manner ready for printing. The interlacing of the image is performed by any conventional software application readily available in the market. Alternatively, commonly available software applications such as Photoshop™, Corel Draw™ and others may be utilized. Once interlaced, the image is reverse printed on the rear or back, planar side of the lenticular sheet, or sometimes printed on paper or film and attached to the back of the lenticular sheet. Reverse printing may be performed in any conventional manner by any convention printing means.
Subsequent to the reverse printing of the interlaced image upon the lenticular sheet, the lenticular assembly is complete. The resulting lenticular assembly or web of lenticular sheet suffers a number of shortcomings. Most significantly, the continuous orientation of the lenticules extending across the entirety of the web governs the orientation of the desired visual effect. Specifically, as a result of the lenticules' continuous orientation, fine print, bar codes or other information not intended to have the desired visual effect are distorted by the effects of the lenticules.
A further problem with the prior art lenticular assemblies is that the lenticules exhibit a high amount of haze when viewing through the sheet due to light rays crossing when out of focus. The haze is caused by surface defects which scatter light, due to the space between the lenses being worn or of improper design causing additional light scattering and due to seeing into adjacent lenticules at low viewer angles. When the lenticular sheet is produced by sheet extrusion processes, additional haze is introduced by distortion, shrinkage and memory effect of the plastic resin during the forming and cooling of the sheet. Prior art teaches that a compound lenticular sheet with concave lenses on one side and convex lenses on the other side give clear distant viewing. However, these lenticular sheets cannot be printed with conventional lenticular images due to the lens arrangement appearing on the side to contain the print.
Accordingly, there is therefore a need for an improved lenticular sheet operable for use in lenticular assemblies that has lenticular lens arrays in at least one pre-selected portion of the sheet and a clear non-lenticular portion to accommodate fine detailed print or for other images in which the lens effect is undesired and would be a determent.